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Arthropods, on the other hand, display a heterogeneous mix of embryonic cleavage patterns including spiral-like cleavage and radial cleavage patterns. This led researchers to two theories: The first was that the arthropods lineage must have lost the ability to spiral cleave since differentiating from the last common ancestor between annelids ...
High Humidity reduces mechanical damage such as brittle paint but raises the risks of biological organisms, e.g. white efflorescence and green-to-black stains on a panel painting. [12] High Humidity also raises the risks of curving or warping of the wood over time, forcing the paint to flake off.
Annelids are members of the protostomes, one of the two major superphyla of bilaterian animals – the other is the deuterostomes, which includes vertebrates. [68] Within the protostomes, annelids used to be grouped with arthropods under the super-group Articulata ("jointed animals"), as segmentation is obvious in most members of both phyla ...
Most living animal species belong to the infrakingdom Bilateria, a highly proliferative clade whose members have a bilaterally symmetric and significantly cephalised body plan, and the vast majority of bilaterians belong to two large superphyla: the protostomes, which includes organisms such as arthropods, molluscs, flatworms, annelids and ...
Marine arthropods range in size from the microscopic crustacean Stygotantulus to the Japanese spider crab. Arthropods' primary internal cavity is a hemocoel, which accommodates their internal organs, and through which their haemolymph - analogue of blood - circulates; they have open circulatory systems. Like their exteriors, the internal organs ...
Although arthropods are essentially direct developers that do not possess a trochophore-like larva, the annelids do. During annelid metamorphosis , segments are added close to the posterior of the body, behind the mouth; whereas the brain is derived from the episphere or region in front of the mouth.
As in all arthropods, the chelicerate body has a very small coelom restricted to small areas round the reproductive and excretory systems. The main body cavity is a hemocoel that runs most of the length of the body and through which blood flows, driven by a tubular heart that collects blood from the rear and pumps it forward.
The arthropods are a phylum of animals with jointed legs; they include the insects, arachnids such as spiders, myriapods, and crustaceans. [1] Insects play many roles in culture including their direct use as food, [2] in medicine, [3] for dyestuffs, [4] and in science, where the common fruit fly Drosophila melanogaster serves as a model organism for work in genetics and developmental biology.